Make the break, Ken

The Conservative party, throughout its history, has been about nothing so much as the possession of power. That is what makes last Thursday's defeat so shattering. Now deprived, apparently for at least a decade, of the cement of the plausible prospect of office, the whole edifice could crumble.

There are great debates about ideas among today's Tories. There is Europe, of course. There are those who really wish to withdraw from the EU and would not accept even a "yes" vote in a referendum. Those who accept EU membership but would fight to secure a "no" vote, while accepting the verdict of the people. Those, now a tiny minority, who would campaign for a "yes" vote. There are the social conservatives and the social liberals. There are those who feel that reconnecting with the voters on their concerns over the nation's health, education and transport infrastructures can only be done by matching, or even, in some areas, exceeding, New Labour's spending commitments. There are those, by contrast, who favour a radical new case for smaller government and greater private provision.

But these pale into insignificance beside the deep desire of Conservative parliamentarians and Conservative activists to be painted a picture, by the leadership candidates, of a fast pathway back to power. The real depth of the current crisis of Conservatism is that there are now two completely contradictory but completely internally consistent pictures of how that can be achieved.

Easily the most straightforward scenario for the destruction of New Labour in this parliament would be if a euro referendum is held and lost. To secure that, it can be argued, the Conservative party must make itself a far more credible instrument of euroscepticism than it is at present. It must purge itself of evasion, of "not for the lifetime of the next parliament", and proclaim the certainties of principled rejection of the euro and all that it entails. It must outline a detailed vision of a new, semi-detached relationship with the EU which, while wholly unrealistic, will, it is imagined, chime with the current underinformed and sceptical convictions of a majority of the British people.

It might well be that to enhance its capacity to defeat the government on the euro, this hardline anti-Europeanism could adopt a more centrist approach in other areas, such as in social and welfare policies, along the lines apparently favoured by Michael Portillo and Francis Maude. Or it might conclude, with Iain Duncan Smith or Ann Widdecombe, that to seek to imitate the softer approach on lifestyle and community issues of New Labour will bring no electoral advantage and that Conservatism in these areas retains widespread, if largely hidden, popular support. But one thing it absolutely could not tolerate is any form of dissent that might blunt its best blow against Blair. All promises notwithstanding, Ken Clarke and his small band of pro-euro followers must be driven out.

But for Clarke himself, for his immediate supporters, and for a further, though not very large, number of Conservative MPs who, though they may not relish the prospect, nevertheless believe that Britain will, sooner or later, join the euro, there is an alternative fast track back to possible power. They could accept the eurosceptics' invitation and leave the party. If the general election result proves anything, it is that a new centre-right grouping, working in alliance with the Liberal Democrats, could be hugely successful. There is a hunger for novelty behind the appallingly low turnout. Only something new can defeat New Labour.

If it remains united, the Conservative party could win a "no" vote in a euro referendum, in which case Clarke's most sincere political conviction about Britain and about Conservatism will have been crushed. But even if the "yes'' camp won, it would still take probably two parliaments for the party to achieve the internal cohesion and external credibility, especially on public services, that could put it again in contention for government. And it might never do so. It is not impossible that the Liberal Democrats may see their best prospects to the left of New Labour and a realignment of British politics takes place by which Blair becomes, even more than he already is, the spokesman for the traditional Conservative constituency. The Conservative party could be driven to the margins and to oblivion. Already, it is far weaker than was Labour even at the depths of its crisis in 1983, when it won 209 seats.

By breaking with the Conservative party now, Clarke would be shedding, at a stroke, all the impedimenta that makes Conservatism so unappealing and so dangerous to the nation. He would be preventing New Labour from becoming New Conservatism. He would be offering Tony Blair a real fight and the people a real and responsible opposition. He would be removing the greatest barrier to Britain's successful engagement in Europe: the absence of a continuing consensus, across both government and opposition, in favour of the EU.

Far from destroying Conservatism's place in government, he would be saving it. Above all, he would be doing what Conservative leadership candidates used to presume: he would be aspiring to be prime minister.